> Stay in one app instead of logging into 2 and checking your email and a website.

The point seems to be that you can pick whatever service you want and will still get the information because it’s repeated across channels. The manager needs to post to all four, but everyone else picks one.

They all can be done through Meetup - I think the point here is that multiple channels avoids vendor lock-in and increases the likelihood that a user will overlap with one of the 4 communication strategies.